You have no "retry" parameter in your syncrepl config, so naturally it
does
not retry. It always helps to actually Read The correct FM, slapd.conf(5)
in
your case.

I'd also note that slapd will issue
syncrepl rid=003 searchbase="ou=tree,ou=name": no retry defined, using
default
if no retry is configured; one should at least wonder what that message
means. I'd favor refusing to start if no retry is configured, since
replication is not reliable without.

That message was added in 2.4, these guys are using 2.3. At this point I've
grown tired of telling people "you're using an obsolete release, you should
upgrade."